This invention generally relates to reclosable pouches, bags or other packages of the type in which material, such as foodstuff, detergent, etc., may be stored. In particular, the invention relates to reclosable packages having slider-operated zippers.
Reclosable bags are finding ever-growing acceptance as primary packaging, particularly as packaging for foodstuffs such as cereal, fresh vegetables, snacks and the like. Such bags provide the consumer with the ability to readily store, in a closed, if not sealed, package any unused portion of the packaged product even after the package is initially opened. To gain acceptance as a primary package for foodstuffs, it is virtually mandatory that the package exhibit some form of tamper evidence to protect the consumer and maintain the wholesomeness of the contained product. In addition, in many cases it is necessary that food product be hermetically packaged.
Reclosable fastener assemblies are useful for sealing thermoplastic pouches or bags. Such fastener assemblies typically include a plastic zipper and a plastic slider. Typically, the plastic zippers include a pair of interlockable profiled members that form a closure. As the slider moves across the profiles, the profiles are opened or closed. The profiles in plastic zippers can take on various configurations, e.g. interlocking rib and groove elements having so-called male and female profiles, interlocking alternating hook-shaped closure members, etc. Reclosable bags having slider-operated zippers are generally more desirable to consumers than bags having zippers without sliders because the slider eliminates the need for the consumer to align the interlockable zipper profiles before causing those profiles to engage.
In one type of slider-operated zipper assembly, the slider straddles the zipper and has a separating finger at one end that is inserted between the profiles to force them apart as the slider is moved along the zipper in an opening direction. The other end of the slider is sufficiently narrow to force the profiles into engagement and close the zipper when the slider is moved along the zipper in a closing direction. Other types of slider-operated zipper assemblies avoid the use of a separating finger. For example, U.S. Pat. No. 6,047,450 discloses a zipper comprising a pair of mutually interlockable profiled closure members, portions of which form a fulcrum about which the profiled closure members may be pivoted out of engagement when the bases of the profiled closure members are forced towards each other.
One problem with reclosable plastic bags of the foregoing type is that, if they are filled with a food product and then sold in a grocery store, the contents can be tampered with prior to purchase by the consumer. Therefore it is desirable to design such packages with a feature that provides evidence of tampering. One such tamper-evident feature is a top enclosure or header that encapsulates the slider-zipper assembly. Typically, means are provided for enabling a top portion of the header to be torn or cut off, thereby giving the consumer access to the slider. The tear line or cut line may be situated at an elevation higher than the top of the zipper so that the zipper does not interfere with tearing away or cutting off of the header top portion. In such cases, the remaining portions of the header on both sides of the zipper cover parts of the slider, thereby limiting the consumer's access to the slider.
It is known to provide a zipper slider with a grab tab that is fixed relative to the slider and projects upward from the top of the slider. When the tear-away portion of the header is removed, the consumer can move the slider by grasping the grab tab. In this case the header must allow for the upward projection of the grab tab, adding to the height of the header. There is a need for a reclosable package in which the slider has a tab that is movable between a storage position and a pulling position, thereby reducing the height of the header and the amount of material needed to construct the header. There is also a need for a slider having a pull tab that can be moved between a first position suitable for grasping by the user for pulling the slider in one direction and a second position suitable for grasping by the user for pulling the slider in the opposite direction.